Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 fixes from Ingo Molnar:
 "The main changes are the PCID fixes from Andy, but there's also two
  hyperv fixes and two paravirt updates"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/hyper-v: Remove duplicated HV_X64_EX_PROCESSOR_MASKS_RECOMMENDED definition
  x86/hyper-V: Allocate the IDT entry early in boot
  paravirt: Switch maintainer
  x86/paravirt: Remove no longer used paravirt functions
  x86/mm/64: Initialize CR4.PCIDE early
  x86/hibernate/64: Mask off CR3's PCID bits in the saved CR3
  x86/mm: Get rid of VM_BUG_ON in switch_tlb_irqs_off()

1 files changed, 20 insertions, 1 deletions

diff --git a/arch/x86/power/hibernate_64.c b/arch/x86/power/hibernate_64.c
index f2598d81cd55..f910c514438f 100644
--- a/arch/x86/power/hibernate_64.c
+++ b/arch/x86/power/hibernate_64.c
@@ -295,7 +295,26 @@ int arch_hibernation_header_save(void *addr, unsigned int max_size)
 		return -EOVERFLOW;
 	rdr->jump_address = (unsigned long)restore_registers;
 	rdr->jump_address_phys = __pa_symbol(restore_registers);
-	rdr->cr3 = restore_cr3;
+
+	/*
+	 * The restore code fixes up CR3 and CR4 in the following sequence:
+	 *
+	 * [in hibernation asm]
+	 * 1. CR3 <= temporary page tables
+	 * 2. CR4 <= mmu_cr4_features (from the kernel that restores us)
+	 * 3. CR3 <= rdr->cr3
+	 * 4. CR4 <= mmu_cr4_features (from us, i.e. the image kernel)
+	 * [in restore_processor_state()]
+	 * 5. CR4 <= saved CR4
+	 * 6. CR3 <= saved CR3
+	 *
+	 * Our mmu_cr4_features has CR4.PCIDE=0, and toggling
+	 * CR4.PCIDE while CR3's PCID bits are nonzero is illegal, so
+	 * rdr->cr3 needs to point to valid page tables but must not
+	 * have any of the PCID bits set.
+	 */
+	rdr->cr3 = restore_cr3 & ~CR3_PCID_MASK;
+
 	rdr->magic = RESTORE_MAGIC;
 
 	hibernation_e820_save(rdr->e820_digest);